7/16" #312 NATIONAL 3 SPLINE DRIVE BACK SPOT FACER PILOT TOOL MT2 MORSE TAPER
7/16" #312 NATIONAL 3 SPLINE BACK SPOT FACER PILOT MT2. REVERSE SPOT FACER HOLDER. For use of holding inverted spot facers or countersinks with #312 (5/16") National 3-spline drive. Arbor shank is #2 Morse taper shank.